Have that book be arguably the most popular of the four. (Debatable with 3 Kingdoms)
The story is told to children since they're young.
During a time where the story was adapted into plenty of derivatives like Dragon Ball, one TV show stood out. Every single Chinese, and Southeast Asian kid has watched it growing up. It was THE weekend TV to wait for. The theme songs are extremely catchy. The TV show is put on reruns every once in a while. Entire nations have watched it.
Then China, who arguably never had a AAA game title this widely marketed before, writes a sequel loosely based on the original novel and lined the game full of homages and music remixes from the TV show.
Western audiences can review however they want, any person who can hear this song in their head "dun dun dudun dun dun dududuuuun pewpewpew pewpewpew" is going to love it even if it's only mildly playable, let alone being actually fun to play.
And have you seen the animations?
If power rangers were a centuries old story, with statues, temples and mythos around them, and it's the first ever AAA game from the US to be published. The moment you hear "Go Go Power Rangers" you're buying the game.